Will they stick after the icing has crusted? Can I just "glue" each one on with a dab of bc icing?

I want it to look like the dotted swiss but with pearls instead of bc dots.

Think it will work?

I've done it but I put them on before the bc had crusted. I would think you could put them on afterwards though if you use a little piping gel or royal or maybe even bc.

Is dotted swiss supposed to go around the cake in alternating rows or just randomly scattered around?

I am almost positive that swiss dots form a pattern around the cake. There's even the version where there are 3 dots grouped together, like an upside down triangle, and the patterned around the cake

Anyone put them on after bc has crusted?

Just use some buttercream as glue.